The present invention generally relates to the field of catheter assemblies for providing a treatment material, such as a drug in fluid form, directly to the vascular system of a mammal. In particular, the invention relates to a device for releasably attaching an end of a catheter to a vascular access port, or other device.
Numerous surgical and non-surgical treatment procedures require that a catheter be placed in fluid communication with a patient's vascular system. A number of devices for this purpose are known. Both implantable treatment reservoirs, such as disclosed in U.S. Pat. No. 4,673,394, and traditional cannula devices afford access to a patient's vascular system, using catheters attached to those devices.
In the prior art, catheters are typically permanently affixed to the implantable device prior to implantation.
It is also known to use an implantable device together with a catheter which are adapted for attachment to a port of that device during the implantation procedure, but after the device is positioned within the patient. Typically, such catheters are adapted to be slidingly placed over a tubular port of the device, and frictionally held in place. Due to the nature of the procedures by which implantable treatment devices are surgically implanted in patients, it is necessary that the connection between a catheter and the implantable device be easily accomplished. This enables a surgeon to concentrate on the proper placement of the implantable device. The friction fit placement of catheters has proved to be very difficult in practice.
While such configurations provide a secure connection, they are undesirable because the permanent connection restricts the degree to which the implantable device can be manipulated, thereby making installation cumbersome. As a result, optimum placement of the implantable device is often achieved only with great difficulty, or sometimes not at all achieved.
Known connectors comprising a mere collar circumscribing the catheter which fits over a male tube projecting from the implantable device often do not afford secure attachment. If the inner diameter of the collar does not properly correspond to the outer diameter of the catheter, either the collar will not fit over the catheter, or the collar will not generate a sufficient compressive force to secure the catheter to the exit port. With known assemblies, therefore, it is necessary to keep on hand a variety of connectors so that a connector can be used which is specifically designed for use with the particular catheter being connected.
U.S. Pat. No. 4,673,394 discloses a particularly effective device for attaching a catheter to an implanted access port. That device is a twist-lockable (bayonet-type) coupler in which a pair of bayonet pins extend in opposite directions from the generally cylindrical outer surface of the coupler. The pins, together with the geometry of the coupler may be slidingly positioned over the tubular port of an access device with a particular angular orientation, and then twisted so that the pins are captively held in place by the portions of the implantable device which defines a void region used to capture the pins.
One problem for this coupler is that the surgeon might encounter difficulty exactly matching the inner diameter of the coupler with the outer diameter of the catheter when it is positioned over the tubular port. Such difficulty would result in corresponding difficulty in attaching the catheter to the port. Moreover, the bayonet coupler must be manually held in place during and until it is sutured in place by the surgeon.
It is, therefore, an object of the present invention to provide an improved connector that will securely attach a catheter to an implantable device.
It is another object to provide a catheter-to-implantable device connector which is easily installed.
It is yet another object of the invention to provide such a connector which can be utilized with a variety of catheters having different diameters.